The paper first of all defines conventional aids to navigation and compares both the historical and future roles of these aids in relation to developments in the field of radio navigation systems and technological advances in shipborne navigational aids. It goes on to emphasize the need to provide for all classes of vessel, i.e. those equipped with a high level of sophisticated shipborne aids and those equipped with a low level of such aids, including the not-so-well-found vessel, fishing vessels and leisure craft. Mention is made of present mandatory requirements in respect of the carriage of electronic shipborne navigational aids and the effect of changes in these requirements on the future role of conventional aids. The availability, reliability, accuracies and errors of both conventional aids and radionavigation systems are discussed. The paper concludes that, with the anticipated developments in the field of radionavigation systems such as Global Maritime Satellite Navigation, GPS, Differential GPS, Loran-C and Differential Loran-C, there may be a decline in the requirement for some conventional aids to navigation; the provision of these aids, however, is seen as still playing an important role in the overall mix of aids to navigation used by the mariner. The level of importance of this role bears a direct relationship to the level of shipborne navigational aids carried by the various classes of vessel and changes in the mandatory requirements for such aids.